| Message ID | 1561661788-22744-20-git-send-email-wahrenst@gmx.net (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | staging: bcm2835-camera: Improvements | expand |
Le jeudi 27 juin 2019 à 20:56 +0200, Stefan Wahren a écrit : > From: Dave Stevenson <dave.stevenson@raspberrypi.org> > > There is an awkward situation with H264 header bytes. Currently > they are returned with a PTS of 0 because they aren't associated > with a timestamped frame to encode. These are handled by either > returning the timestamp of the last buffer to have been received, > or in the case of the first buffer the timestamp taken at > start_streaming. > This results in a race where the current frame may have started > before we take the start time, which results in the first encoded > frame having an earlier timestamp than the header bytes. > > Ensure that we never return a negative delta to the user by checking > against the previous timestamp. > > Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.org> > --- > drivers/staging/vc04_services/bcm2835-camera/bcm2835-camera.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/drivers/staging/vc04_services/bcm2835-camera/bcm2835-camera.c b/drivers/staging/vc04_services/bcm2835-camera/bcm2835-camera.c > index 9967df9..6205793 100644 > --- a/drivers/staging/vc04_services/bcm2835-camera/bcm2835-camera.c > +++ b/drivers/staging/vc04_services/bcm2835-camera/bcm2835-camera.c > @@ -387,6 +387,11 @@ static void buffer_cb(struct vchiq_mmal_instance *instance, > ktime_to_ns(dev->capture.kernel_start_ts), > dev->capture.vc_start_timestamp, pts, > ktime_to_ns(timestamp)); > + if (timestamp < dev->capture.last_timestamp) { > + v4l2_dbg(1, bcm2835_v4l2_debug, &dev->v4l2_dev, > + "Negative delta - using last time\n"); > + timestamp = dev->capture.last_timestamp; > + } Instead of that, maybe you could request a minimum number of buffers, and not let the header buffer go until you have a proper "following timestamp" to give it. This way you don't need this hack, and you won't have an off-by-one in timestamps. > buf->vb.vb2_buf.timestamp = ktime_to_ns(timestamp); > } else { > if (dev->capture.last_timestamp) { > -- > 2.7.4 >
diff --git a/drivers/staging/vc04_services/bcm2835-camera/bcm2835-camera.c b/drivers/staging/vc04_services/bcm2835-camera/bcm2835-camera.c index 9967df9..6205793 100644 --- a/drivers/staging/vc04_services/bcm2835-camera/bcm2835-camera.c +++ b/drivers/staging/vc04_services/bcm2835-camera/bcm2835-camera.c @@ -387,6 +387,11 @@ static void buffer_cb(struct vchiq_mmal_instance *instance, ktime_to_ns(dev->capture.kernel_start_ts), dev->capture.vc_start_timestamp, pts, ktime_to_ns(timestamp)); + if (timestamp < dev->capture.last_timestamp) { + v4l2_dbg(1, bcm2835_v4l2_debug, &dev->v4l2_dev, + "Negative delta - using last time\n"); + timestamp = dev->capture.last_timestamp; + } buf->vb.vb2_buf.timestamp = ktime_to_ns(timestamp); } else { if (dev->capture.last_timestamp) {